We have demonstrated laser operation of an AlGaN multiple-quantum-well (MQW) laser diode (LD) with a peak wavelength of 336.0 nm under pulsed current mode at room temperature. The LD was fabricated on a low-dislocation-density Al0.3Ga0.7N grown on a sapphire substrate using a hetero-facet-controlled epitaxial lateral overgrowth method. The laser emission is strongly transverse electric polarized with a peak output power of 3 mW and a differential external quantum efficiency of 1.1%. This demonstration of the LD lasing in ultraviolet-AII spectral band (320–340 nm) suggests that the AlGaN MQW LDs can be potent devices opening a path to deeper ultraviolet LDs.

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ALG-2, a member of the penta-EF-hand protein family, interacts Ca²+-dependently with a COPII component, Sec31A. In this study, we first established HeLa cells stably expressing green fluorescent protein-fused ALG-2 (GFP-ALG-2) and red fluorescent protein-fused Sec31A (Sec31A-RFP). After inducing Ca²+-mobilization, the cytoplasmic distribution of GFP-ALG-2 changed from a diffuse to a punctate pattern, which extensively overlapped with the Sec31A-RFP-positive structures, indicating that ALG-2 is recruited to the endoplasmic reticulum exit sites (ERES) in living cells. Next, overlay experiments with biotin-labeled ALG-2 were done to dissect the ALG-2 binding site (ABS). They revealed that a sequence comprising amino acid residues 839-851 in the Pro-rich region was necessary and sufficient for direct binding to ALG-2. Finally, fluorescence recovery after photobleaching analysis indicated that the ABS deletion reduced the high-affinity population of Sec31A to the ERES, suggesting that the ABS is one of the key determinants of the retention kinetics of Sec31A at ERES.

An ultraviolet (UV)-light-source tube using a Si-doped AlGaN film as a target of electron beam excitation was fabricated. The Si-doped AlGaN was grown on an AlN/sapphire substrate by low-pressure metalorganic vapor phase epitaxy (LP-MOVPE), and its optical properties were evaluated by excitation with a 10 kV electron beam (EB). Emission intensity was significantly improved by Si doping and optimization of the growth conditions. 247 nm deep-UV light was observed from the tube, and the lifetime of the light tube until 50% emission output of the initial strength was approximately 2000 h at an EB acceleration voltage of 10 kV with a current of 100 µA.

ALG-2, a prototypic member of the penta-EF-hand protein family, interacts with Alix at its C-terminal Pro-rich region containing four tandem PXY repeats. Human phospholipid scramblase 3 (PLSCR3) has a similar sequence (ABS-1) in its N-terminal region. In the present study, we found that ALG-2 interacts with PLSCR3 expressed in HEK293 cells in a Ca 2؉ -dependent manner by co-immunoprecipitation, pulldown with glutathione S-transferase (GST) fused ALG-2 and an overlay assay using biotin-labeled ALG-2. The GST fusion protein of an alternatively spliced isoform of ALG-2, GST-ALG-2 ⌬GF122 , pulled down green fluorescent protein (GFP)-fused PLSCR3 but not GFP Alix. Deletion of a region containing ABS-1 was not sufficient to abrogate the binding. A second ALG-2-binding site (ABS-2) was essential for interaction with ALG-2 ⌬GF122 . Real-time interaction analyses with a surface plasmon resonance biosensor using synthetic oligopeptides and recombinant proteins corroborated direct Ca 2؉ -dependent binding of ABS-1 to ALG-2 and that of ABS-2 to ALG-2 as well as to ALG-2 ⌬GF122 . The sequence of ABS-2 contains multiple prolines and two phenylalanines, among which Phe 49 was found to be critical, because its substitution with Ala or Tyr caused a loss of binding ability by pulldown assays using oligopeptide-immobilized beads. ALG-2-interacting proteins were classified into two groups based on binding ability to ALG-2 ⌬GF122 : (i) isoform-non-interactive (ABS-1) types, including Alix, annexin A7, annexin A11, and TSG101 and (ii) isoform-interactive (ABS-2) types including PLSCR3, PLSCR4 and Sec31A. GST-pulldown assays using single amino acid-substituted ALG-2 mutants revealed differences in binding specificities between the two groups, suggesting structural flexibility in ALG-2-ligand complex formation.

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The use of the Phillips–Tikhonov regularization is proposed for numerically stabilizing the ill-conditioned plasma image reconstructions. An objective function to be minimized leads to a linear estimator of the image intensity distribution and, with the aid of the singular value decomposition, makes it possible to use the generalized cross validation for optimizing a regularization parameter. An excellent behavior of the estimator with computational facility is obtained on the Hα emission computerized tomography of a toroidal plasma.